Rotating actuator

ABSTRACT

A rotating actuator displaces a movable pin between two end positions, at least one of which two end positions is a stop. The actuator comprises an energy buffer, components mutually connecting the energy buffer and the movable pin, a mass capable of storing energy of the energy buffer as kinetic energy, wherein at the end of the displacement in at least one direction the kinetic energy of the mass is stored again in an energy buffer. A locking device blocks the actuator in at least one extreme position when the remaining kinetic energy has been substantially transferred to the energy buffer. The lost energy can be supplied at the end of the movement cycle. Between the energy buffer and the movable pin are situated at least two rotating components, i.e., an actuating element which drives the movable pin between two end positions. The distance between the end positions in relation to each other is not necessarily determined. A mass which moves along partly parallel with the actuating element, wherein kinetic energy is stored in the mass at the beginning and over only a part of the movement, on the basis of which kinetic energy the movement of the rotating components can be completed without other energy sources having to be applied for this purpose and whereof at the end of the movement the mass can rotate further relative to the actuating element, wherein the remaining kinetic energy of the mass is relinquished to the energy buffer.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The invention relates to an actuator for displacing a movable pinbetween two end positions, at least one of which two end positions is astop, comprising an energy buffer, components mutually connecting theenergy buffer and the movable pin, a mass capable of storing energy ofthe energy buffer as kinetic energy, wherein at the end of thedisplacement in at least one direction the kinetic energy of the mass isstored again in an energy buffer, locking means which block the actuatorin at least one extreme position when the remaining kinetic energy hasbeen wholly or almost wholly generated to the energy buffer, and meanswith which at the end of the movement cycle the lost energy can besupplied to for instance a locking, switch or press or hammer device forinstance for compacting, deforming, reinforcing and/or ejectingmaterial.

2) Background Information

Such an actuator is known for instance from EP-B-0 107 881.

An object of the invention is to arrive at an inexpensive and compactactuator which, irrespective of the direction of the gravitational forceand irrespective of the presence of external energy sources such as amains electricity supply or for instance an external accumulatorbattery, is capable of actuating the movable pin time and again in thecorrect manner and of realizing the required pressure between movablepin and the stop.

The invention furthermore has for its object to be used for the purposeof rotating as well as non-rotating pins.

The invention moreover has for its object to be used on actuatorswherein the distance between the two end positions is not fixedprecisely as a consequence of wear or inaccurate production processes orbecause the stop is not defined at all due to the nature of theapplication, for instance the use for machining material wherein theactuator forms part of an apparatus which is held at an imprecisedistance from the material for working.

SUMMARY OF THE INVENTION

These objectives are generally realized by an actuator which has thefeature that between the energy buffer and the movable pin are situatedat least two rotating components, i.e. an actuating element which drivesthe movable pin between two end positions, whereof the distance betweenthe end positions in relation to each other is not necessarilydetermined, and a mass which moves along partly parallel with theactuating element, wherein kinetic energy is stored in the mass at thebeginning and over only a part of the movement, on the basis of whichkinetic energy the movement of the rotating components can be completedwithout other energy sources having to be applied for this purpose, andwhereof at the end of the movement the mass can rotate further relativeto the actuating element, wherein the remaining kinetic energy of themass is relinquished to the energy buffer.

The device comprises an actuator which displaces one (or more) pin(s)which may or may not be rotatably movable and which must be movedthrough a certain, not necessarily defined, distance or angle from theone end position to the other and back again,

wherein at least one end position is characterized by a stop, whereinthe pin is held fixedly in both or in one of the end positions by thelocking forming part of the actuator and can be released again asrequired,

wherein in at least one of the two end positions the pin exerts acertain pressure on its stop, and

wherein the actuator also contains energy means which store the energyin the form of potential energy in at least one of the end positions,

wherein potential energy is generated to the actuator during only a partof the displacement, wherein potential energy is converted into kineticenergy which is in turn stored in the mass forming part of the actuator,

wherein at the end of the movement the remaining kinetic energy is againconverted into potential energy and vice versa, and

wherein the device also comprises means for energy supply which at theend of the movement are able to supply the lost energy in the form ofpotential energy to the energy buffer,

wherein it is possible to cause the speeds of the movable pin to belargely independent of the gravitational force and wherein withcomparatively simple locking means a precise locking of the pin ispossible as close as possible to the point where all kinetic energy isstored as potential energy.

The invention is based on a favourable energy management and compactconstruction, whereby using known and compact forms of energy storage inthe actuator or as component of the device of which the actuator deviceforms part, independently operating machines can be made.

For this purpose it makes use of one or more energy buffers in whichpotential energy is stored and which, after they have relinquished theirenergy in the form of kinetic energy for displacement of the movable pinwith associated parts, also gradually store again the remaining kineticenergy at the end of the movement.

The thus realized small energy losses results in the use of lightercomponents for acceleration, whereby the total required energy contentcan be smaller, which itself again results in smaller losses etc. Thisprinciple also has the advantage that braking of the parts takes placegradually, whereby no sudden large collision forces occur wherebyconstructions can be made lighter. Lighter masses moreover result in perse smaller forces, whereby constructions can again be made lighter,which again also results in lighter masses. Furthermore, when energylosses are small, they can easily be supplemented from compact andrelatively cheap forms of energy storage which form part of the actuatoror device of which the actuator forms part, whereby the object of theinvention is fulfilled.

The invention is based inter alia on the application of rotating massesand components, whereby the influence of the direction of thegravitational force for the relevant rotating parts is eliminated andwith which in very simple manner rotating pins can likewise be operated.

The invention is likewise based on a construction such that locking cantake place accurately and effectively with simple locking means, wherebythe actuator can be produced more simply and therefore inexpensivelywhile at least retaining a good energy efficiency.

Attention is drawn to the patents U.S. Pat. No. 3,248,497, U.S. Pat. No.1,872,382, U.S. Pat. No. 3,811,022, FR-A-2 092 316 and CH-A-347 244.

These patents relate to a switch wherein a contact pin is moved againsta stop and wherein in order to build up contact force or to preventcontact bouncing or to prevent undesired vibrations, spring and/orspring damping constructions are used parallel to or between theactuator and the contact pin. The energy stored in these springconfigurations during switch-on becomes available again in these casesfor the greater part or for only a small part at switch-off. In none ofthese inventions however is there a process wherein potential energy isfirst converted into kinetic energy for the purpose of the movement,wherein the movement is completed only, or practically only, on thebasis of the kinetic energy and where at the end of the movement theremaining kinetic energy is again stored as potential energy, whichenergy wholly or largely provides the return movement.

The drawback to all these actuators is that they do not fulfill theintended objective in respect of favourable energy management,simplicity, compactness and the independence of the direction of thegravitational force.

The properties of such an actuator are described in EP-B-0 107 881. Thisactuator is used to displace a movable element between two endpositions.

This actuator consists of a linearly moving mass which is directlycoupled to a movable pin which moves between two end positions and whichis operated by a cylindrical spiral spring which is incorporated in themass and which first slackens over a certain distance, thereinaccelerating the movable pin and the mass, whereby potential energy ofthe spring is converted into kinetic energy of the mass. For thispurpose the spring supports on one side on the movable pin and on theother side against a stop which forms part of the housing of theactuator and for this purpose penetrates into the mass in order to beable to reach the spring end.

At the end of the stroke wherein potential energy is converted intokinetic energy, the assembly of mass, pin and spring moves further,whereby the desired distance is spanned on the basis of the built-upkinetic energy and without further addition of energy until the movablepin reaches the stop, whereafter the mass, due to its kinetic energy, iscapable of running on through a certain distance, therein slightlytensioning the spring again.

This actuator likewise contains locking means which lock the mass in orclose to the extreme positions, wherein the degree to which the lockingmeans are successful in locking the mass when the kinetic energy is zerois a measure for the degree to which the energy conversion process iseffective.

All the proposed actuators, including the intended invention, are basedinter alia on the principle of energy conversion, wherein potentialenergy for the purpose of a displacement is converted into kineticenergy and vice versa as soon as the movement is completed. Thisprinciple is known from physics and is much used in actuators indifferent forms, for instance in the form of a pendulum principle,either modified or not, such as is also found in clock mechanisms.

The drawback to the apparatus described in EP-B-0 107 881 lies amongother things in the co-action between the mass and the possible lockingmeans. Particularly where this is applied for actuating moving pinswherein the actuating mass only runs on over a small distance, as aresult for instance of the desired small energy content and the use ofsprings with a high spring constant in combination with a high biasedforce of the spring with the object of keeping the actuator compact andalso to be able to provide the desired force between moving pin andstop, such as is desired for instance in the case of switch contacts.

It will in any case be found in practice to be impossible or verydifficult to make a locking means which receives and locks the massprecisely when it becomes stationary, which is therefore when allkinetic energy is stored in the spring. Account will always have totaken that this takes place a certain distance too early or too late.Because this distance is determined by the quality of the locking anddoes not depend on the distance over which the mass runs on after themovable pin has reached one of its end positions, it will be apparentthat when the actuating mass runs on over a small distance the energylosses are relatively greater than in the case of a large distance.

In practice therefore it will be necessary for the purpose of lockingthe linear mass either to apply particularly complex and expensive lockswhich engage very precisely, or to connect to the mass an extra masswhich acquires a greater stroke by means of a conversion mechanism andon which relatively simple locking means can already engage efficiently,which is in itself a significant complication of the actuator andmoreover results in all kinds of undesired adaptations between the twomutually connected masses.

Another drawback to the actuator as described in EP-B-0 107 881 is thatthe speed of the movable pin is influenced by the position which itoccupies in relation to the gravitational force. Whether thegravitational force assists or hinders the actuating linear mass willhave a great influence on the speed of the movable pin. This is all themore of a drawback since reducing the size of the mass, whereby thesensitivity to the gravitational force decreases, is not possible incombination with a higher speed, so that the energy product remains thesame, as the mass is directly coupled to the movable pin and the speedof the movable pin is usually prescribed.

The dependence on the direction of the gravitational force will entail asignificant obstacle to use if the actuator is used for instance for amodular device which it must be possible to place or use in differentsystems and in different, still unknown positions relative to thegravitational force.

Another drawback to the said actuator is that the outward speed of themovable pin, thus immediately after slackening of the spring, is alwayshigher than during the second cycle when the movable pin returns to itsoriginal position. The energy loss which will inevitably occur duringthe outward movement will anyway result automatically in a lower returnspeed.

This is an important drawback in the case the actuator is used todisplace for instance the movable contact pin of switches, wherein theenergy buffer is charged in switched-off position and wherein theswitch-on speed may be lower than the switch-off speed. If this optionof a lower switch-on speed is not utilized, the average speed thenbecomes higher and thereby the amount of energy which is involved andthus also lost. Unnecessarily high speeds moreover result in greaterforces, whereby heavier components are required, which in turn resultsin greater amounts of energy etc.

Another disadvantage of the said actuator is that the direct coupling ofthe mass to the movable pin allows no other than a direct and linearmovement relation between mass and movable pin. Adapting of the speeds,for instance just prior to the moment of contact between the movable pinand the stop in order thereby for instance to reduce the degree ofcollision, is thereby not possible.

Another drawback of the said device is that it is wholly based onactuation of a movable pin for linear displacement.

Due to these drawbacks this device also does not comply with thedifferent points stated as the objective.

The invention has for its object to largely obviate all the above statedobjections while retaining the obtained advantages and properties,whereby the objective is achieved to the fullest possible extent.

In the preferred embodiment the actuator consists of:

A rotating actuating element or an assembly of actuating elements towhich the rotating pin or, via a converting mechanism the non-rotating,for instance linearly moving pin, is fixed and which displace the pinbetween two end positions, wherein at least one end position is definedby a stop.

A spring or an assembly of springs which is fixed to the ends betweenthe actuating element and the frame or housing of the actuator and whichin tensioned state has available sufficient energy to displace the pinin outward and return direction, wherein the spring drives the actuatorover only a part of the angular displacement.

and which is also capable to provide the required pressure with whichthe pin must be pressed against the stop.

A rotating flywheel or an assembly of flywheels of which the axis ofrotation does not have to coincide with that of the actuating element,which co-rotates with the actuating element and which is capable ofstoring potential energy from the spring as kinetic energy, so that thiscan keep going the movement of the actuating element at the moment thespring ceases to generate energy, wherein at the end of the movement theflywheel moreover gives back the remaining kinetic energy to the springwhich is thereby able to build up the desired force with which the pinmust be pressed against the stop.

One or more stops between actuating element and flywheel which providesthe coupling between the two in one actuating device such that thecomponent actuated by the spring is able to carry the other componenttherewith in its rotation.

One or more locking devices for one or both end points which engage onthe flywheel and which are capable of leaving the flywheel in freerotation during conversion of remaining kinetic energy into potentialenergy in the spring, and of automatically blocking the flywheel at themoment that, under the influence of the force of the spring, theflywheel reverses its direction of rotation. The locks are also providedwith unblocking means which release the flywheel at the moment this isdesired.

A spring tensioning device which supplements the lost energy in thespring at the end of the movement cycle.

A frame or housing to which the stops and rotation points of the deviceare fixed.

As drive force for the actuator use is made of a spring, but the forcecan equally be derived from a system of springs or from another form ofenergy storage, provided that this has sufficient power available toprovide the movable pin with the correct movement conditions.

In the case the actuator is used for actuating a non-rotating, forinstance linearly moving pin, the conversion from the rotating to thenon-rotating movement can then take place in any usual manner. Notimportant herein is the manner in which the axes of one or both rotatingmain parts are placed relative to the movable pin.

The flywheel can consist of a number of flywheels which, on the basis ofthe preferred embodiment, are placed between, adjacently of or on eitherside of the actuating element.

The actuating element which contains the rotating pin or to which thenon-rotating movable pin is fixed is driven by the spring over only apart of its stroke, wherein it carries the flywheel along in itsmovement by means of for instance a stop.

At the end of this stroke the flywheel takes over the supporting pointof the spring on the frame by means of a stop, whereafter the spring isenclosed between actuating element and flywheel without being able toslacken further. The flywheel and the actuating element now carry thespring along in their movement until the movable pin, and therewith theactuating element, come to a standstill against the stop. The flywheelis now able to run on relative to the actuating element counter to thespring pressure, whereby it gradually brakes, wherein kinetic energy isstored in the spring until the flywheel comes to a standstill, whereuponthe locking blocks the flywheel in this extreme position.

The energy which is thus stored in the spring is the energy with whichthe return movement must be realized which, as a result of theinevitable energy losses, will of course thereby be performed at a lowerspeed than the outward movement.

The spring which is locked in this position between the flywheel and theactuating element will slacken as soon as the locking once againreleases the flywheel. The spring now actuates the flywheel until itencounters and carries along in its movement the stop or the supportingpoint of the actuating element. The spring then remains enclosed betweenthe flywheel and the actuating element, but now in biased position.

In order to return to the original position at a higher speed, thecoupling between the flywheel and the actuating element consists of twostops or of one stop with a number of contact points.

These different contact points lie one after another as seen in thedirection of movement and thereby result in different positions of theflywheel and the actuating element relative to each other and signifydifferent energy contents for the spring enclosed between the flywheeland the actuating element.

Since the pressure on the contact point between actuating element andflywheel falls away during the outward movement, after the actuatingelement has come to a standstill and the flywheel continues further thiscontact point can be displaced in simple manner, for instance by aspring, such that the second supporting point lying thereafter becomesavailable for the return movement. This second supporting point has theproperty that it allows a larger angle of relief of the flywheelrelative to the actuating element. The spring can thereby generate moreenergy to the flywheel than the flywheel has stored in the spring duringthe outward movement, which will immediately result in higher speedsduring the return movement.

Without being driven the assembly of rotating parts and the spring nowcontinue further due to spring force until the spring end not connectedto the actuating element again encounters its original supporting pointof the frame or housing of the actuator. At that moment this supportingpoint on the frame will replace the supporting point on the flywheel.

The flywheel now rotates further under the influence of its own kineticenergy, therein pushing the actuating element before it by means of thestop, whereby the spring is tensioned, until all kinetic energy isconverted into potential energy and the flywheel will come to astandstill, whereafter locking means engage on the flywheel, therebylocking the flywheel and the actuating element in their extremeposition.

A spring tensioning device can subsequently begin to tension the springuntil the original position is assumed. It will do this for instance bycausing a curve path to act on a point of the actuating element so thatthe actuating element moves further counter to the spring pressure,therein tensioning the spring, wherein it is not important, withinlimits, where the actuating element has come to a standstill. Othermethods of supplying energy are also conceivable however, such asmanually, magnetically, pneumatically etc.

During spring tensioning the retracted first stop or contact point willbe able to resume the original position due to the presence at thatlocation of for instance a resilient stop which, counter to theresetting force of the spring of the first stop, pushes this back to theoriginal position.

At the end of the spring tensioning path the actuating element willmoreover carry along the flywheel by means of a stop appropriate forthis purpose so that the actuating element is carried back together withthe flywheel into the original starting position. Due to its directionalsensitivity the locking will allow this tensioning movement.

At the end of the spring tensioning path the spring is tensioned, thecurve disappears from the path of the actuating element, whereby underthe influence of the spring force this latter will come to lie againstthe first stop between actuating element and flywheel, which hasmeanwhile returned fully to the original position.

The locking now also blocks the actuating element via flywheel and stop,wherein the stop is once again fixed for the outward movement by thecontact pressure.

Another conceivable embodiment is one wherein the spring is sub-dividedinto two springs, wherein the function of accelerating the rotatingparts of the actuator is provided by a second spring which does not formpart of the rotating parts but which is fixedly mounted with its oneouter end to the frame and with its other outer end co-acts with theactuating element such that in the starting position the spring, whereofthe stroke over which it can slacken is limited, drives the actuatingelement through an angle which corresponds with this limited stroke,which element then moves further together with the flywheel. The firstspring which forms part of the assembly of rotating parts has the samefunction and therefore also property as described above but withoutproviding the kinetic energy for the outward movement.

Equally conceivable is another embodiment wherein the second spring isused to provide additional energy for the purpose of the returnmovement, wherein it is also able to store kinetic energy. For thispurpose this spring is fixed with the one outer end to the frame and atthe end of the outward movement of the actuating element the flywheelencounters the other end of the spring, therein generating energy storedin the spring.

Also conceivable is the embodiment which is a combination of the abovedescribed embodiments, wherein use is thus made of two springs which donot form part of the assembly of rotating parts and wherein the onespring provides energy for the outward movement and the other spring forthe return movement. This embodiment can exist with or without theoriginal spring forming part of the assembly of rotating parts.

Use of one or more flywheels, wherein the mass is distributed uniformlyrelative to its axis of rotation, results in the direction of thegravitational force having no effect on the speeds.

Basing the actuator on the application of the principle that potentialenergy is converted into kinetic energy and vice versa achieves thatvery little energy will be required to perform the movement, wherebylight and inexpensive construction is possible.

By using a flywheel as mass and by causing the locking means to engageon or close to the outside of the flywheel, a significant increase inthe displacement on its outside can be realized in very simple manner byselecting a sufficiently large diameter, whereby the engagement oflocking means with the inevitable rearward displacement of the mass as aresult of plays, elasticities and inaccuracies results in only a verysmall angular displacement and thus little energy loss. The actuatorthereby remains simple and inexpensive while retaining a large degree ofefficiency.

By using a rotating actuating element both non-rotating and rotatingpins can be actuated in simple manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated with reference to the embodiments shownin the schematic figures.

A possible production embodiment, with several variants thereof, will bedescribed with reference to the following drawings.

FIGS. 1-2 show the actuator, wherein a linearly moving pin is actuated.In the drawn position the actuator is ready to actuate the pin.

FIGS. 3-4 show details of the actuator in respect of the resetting ofthe connecting stop between flywheel and actuating element, in additionto the manner of connecting the vertically moving pin and the actuatingelement.

FIGS. 5-8 show the different positions of the outward movement.

FIGS. 9-12 show the different positions of the return movement.

FIGS. 13-16 show the different positions of the movement during chargingwith energy.

FIG. 17 shows the actuator, wherein the central actuating spring is usedfor the return movement and an additional spring is used for the outwardmovement.

FIG. 18 shows the actuator, wherein the central actuating spring is usedfor the outward movement and an additional spring is used for the returnmovement.

FIG. 19 shows the actuator, wherein the central actuating spring is notused, or is only used in supportive manner, to enable the movement andis substantially designed to supply sufficient pressure of the pinagainst the stop, and wherein for the outward movement use is made of anadditional spring, while an additional spring is also applied for thereturn movement.

FIG. 20 shows the actuator, wherein a rotating pin is actuated andwherein the actuator is shown in the position prior to the outwardmovement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The operation will be elucidated with reference to FIGS. 1-20. Insofaras appropriate, corresponding components are always designated with thesame reference numerals.

The spring 1, which is tensioned in the starting position, in this caseof the opened position of the movable pin 4, is situated adjacently ofor between one or more flywheels 2 and the actuating element 3 of themovable pin 4. The spring is fixed with one outer end to actuatingelement 3. The other spring end 6 supports against the stop 7 of frame8. The actuating element 3 supports against stop 9 of flywheel 2. Thelocking 10 which engages on flywheel 2 prevents slackening of the spring1 (see FIGS. 1 and 2).

The release of the flywheels 2 by the locking 10, for instance by anelectric coil (not shown), sets the flywheel 2 and actuating element 3into movement through a defined free angle 20. Sufficient kinetic energyis herein stored in flywheel 2 for both the outward and the returnmovement. At the end of the free angle 20 the stop 11 of flywheel 2strikes the spring end 6 and subsequently carries it along in itsmovement. The spring 1 is then enclosed between the stop 11 of flywheel2 and the mounting 5 of actuating element 3 and generates no furtherenergy (see FIGS. 5-6).

In free movement the assembly of flywheel 2, spring 1, actuating element3 and movable pin 4 moves to the stop 12. Having arrived there, themovable pin 4 and the actuating element 3 connected thereto stop (seeFIG. 7).

The flywheel 2 can now rotate further counter to the spring pressure,wherein the contact with stop 9 is lost, whereby kinetic energy from theflywheel 2 is stored in spring 1. Once the kinetic energy is fullyconverted, whereby under the influence of the spring force of spring 1the flywheel 2 will want to initiate a reverse movement, the lockingdevice 13 will then block flywheel 2 (see FIG. 8).

During the outward movement, immediately after the movable pin 4 makescontact with stop 12, the stop 9 on flywheel 2 is relieved by running onof flywheel 2. Under the influence of for instance a spring 16 the stop9 shoots aside out of the path of the actuating element 3 (see FIGS.3-4). The next stop in the path of actuating element 3 is now stop 14.For the return movement the spring 1 can thus slacken over a greaterangle 21 than during the outward movement, whereby a higher speed isrealized (see FIGS. 9-10).

For the return movement the locking 13 is released in a manner analogousto that during outward movement. The released spring 1 slackens over thenow enlarged angle 21 wherein flywheel 2 is accelerated without theactuating element 3 being carried along in the movement. The stop 14 offlywheel 2 subsequently strikes against the end of its path and therebyagainst actuating element 3 (see FIG. 7).

The spring 1 does not now slacken further, whereupon flywheel 2, spring1 and actuating element 3 with the movable pin 4 coupled thereto arecarried along in the return movement without the spring 1 generatingfurther energy. At the end of the rotation the outer end 6 of spring 1comes to a standstill against the stop 7 of frame 8 (see FIG. 11).

Under the influence of the remaining kinetic energy the flywheel 1rotates further counter to the spring force until all the kinetic energyis converted into energy of the spring 1, wherein the spring isgradually tensioned. The flywheel 2 stops and is locked againstdirection reversal by the locking device 10 (see FIG. 9).

Once the flywheel 3 has come to a stop and is locked, the lost energy isthen supplemented by a spring tensioning device 15 by returningactuating element 3 to the original position counter to the springtension of spring 1, wherein the stop 9 can return to its originalposition under the influence of a resetting spring 19 of frame 8 (seeFIGS. 3, 4, 13, 14, 15, 16).

A second embodiment relates to the actuator which is provided with anadditional spring 23 for the outward movement. The spring 1 can hereinrelinquish energy to the actuator as described above, therein supportedby the additional spring 23, but can also be applied such that spring 23generates all energy for the outward movement. In this embodiment (seeFIG. 17), in the position preceding the outward movement the centralspring 1 is mounted with the outer end 5 with actuating element 3, whilethe other outer end supports on stop 11 of flywheel 2. The energy forthe outward movement comes from the additional spring 23 which in thisposition is enclosed between the stop 22 of the frame and the cam 11 offlywheel 2. The spring 23 is released by the locking 10, whereafter theadditional spring 23 can relinquish energy to the flywheel until it isbounded by stop 24, whereafter as described above the assembly offlywheel 2 and actuating element 3 completes the outward movement infree motion. In this embodiment the return movement takes place asdescribed above (see FIG. 17).

A third embodiment relates to the actuator provided with an additionalspring 25, the stop 27 of frame 8 and the stop 26 which bounds thestroke of spring 25, wherein this spring generates energy to theactuator for the purpose of the return movement in a manner comparableto that of the additional spring 23 for the purpose of the outwardmovement (see FIG. 18).

A fourth embodiment relates to the actuator provided with an additionalspring 23 for the outward movement and an additional spring 25 for thereturn movement, wherein spring 1 may or may not be used for support andis used mainly to supply sufficient pressure between pin and stop ifthis is required (see FIG. 19).

A fifth embodiment relates to the actuator which drives against the stop29 a rotating pin 28 which can form part of or is connected to theactuating element 3, which stop 29 is connected to frame 8 and whereinthe actuator is otherwise constructed in a manner as described above(see FIG. 20).

I claim:
 1. An actuator for displacing a movable pin between two endpositions, at least one of which two end positions is a stop, comprisingat least one energy buffer, components mutually connecting the energybuffer and the movable pin, a mass adapted to store energy of the energybuffer as kinetic energy, wherein at the end of displacement of the massin at least one direction the kinetic energy of the mass is stored inone energy buffer, locking means which block the actuator in at leastone extreme position when the remaining kinetic energy has beensubstantially transferred to the energy buffer, and means with whichenergy can be supplied at the end of the movement cycle,wherein betweenthe energy buffer and the movable pin is situated an actuating elementwhich drives the movable pin between two end positions, and the masswhich moves along partly parallel with the actuating element, whereinkinetic energy is stored in the mass over a part of the movement, on thebasis of which kinetic energy the movement of the actuating element canbe completed without other energy sources having to be applied for thispurpose and whereof at the end of the movement the mass can rotatefurther relative to the actuating element, wherein the remaining kineticenergy of the mass is relinquished to the energy buffer.
 2. The deviceas claimed in claim 1, wherein the actuator forms part of a frame inwhich the energy buffer forms part of an assembly of rotating parts,which energy buffer is adapted to contain sufficient energy for both theoutward and return movements and whereof in the starting position, whenthe energy buffer is fully charged, the one outer end of the energybuffer is fixedly connected to the actuating element and the other outerend supports on a stop of the frame and wherein the rotating mass whichis carried along in the movement by the actuating element is providedwith a stop such that after a certain angle this stop comes up againstthat outer end of the energy buffer which supports on the stop of theframe, whereby this stop on the mass takes over the supporting point,whereafter the energy buffer is enclosed between mass and actuatingelement and generates no further energy, whereafter the actuatingelement, rotating mass and energy buffer together rotate further untilthe movable pin, and therewith the actuating element, strikes againstits stop, whereafter the rotating mass can rotate further relative tothe actuating element, wherein the contact via the collective supportingpoint is broken, whereby the kinetic energy is converted into potentialenergy of the energy buffer whereby the rotating mass brakes and comesto a standstill, wherein the energy buffer also exerts a pressure on thestop via the actuating element, whereafter locking means engage andblock the actuator, whereafter the return movement can be initiated onthe basis of the energy stored in the energy buffer, wherein themovement proceeds with the outward movement wherein the energy bufferfirst actuates the mass, whereafter by means of the collectivesupporting point the actuating element is carried along in the movementof the mass.
 3. The device as claimed in claim 2, wherein at least oneend position of the actuator locking means engage on the mass generallyat the moment it comes to a standstill, in the direct vicinity of theoutside of the rotating mass so that in simple manner, by choosing acomparatively large diameter of the mass, a sufficiently largeperipheral path can be obtained, whereby the inevitable fall-back angleresulting from elasticity, play and inertia of the locking can be keptvery small, whereby energy loss as a result of the fall-back remainslimited.
 4. The device as claimed in claim 2, wherein for contactbetween mass and actuating element two stops placed one after anotherare applied which are used sequentially, the first stop of which is usedduring the outward movement, which stop, at the moment that the massmoves further in relation to the actuating element, is removed from theplane of movement of the mass in relation to the actuating element,whereby the stop located thereafter becomes available for the returnmovement, thus achieving that the angle through which the energy buffercan slacken is greater than the angle at which the mass generated itskinetic energy to the energy buffer, with the result that a greaterreturn speed can be achieved than without this provision.
 5. The deviceas claimed in claim 1, the actuated pin is associated with the actuatingelement, wherein the actuated pin is rotatable.
 6. The device as claimedin claim 1, wherein the actuated pin is non-rotatable and is connectedto the actuating element via a conversion mechanism.
 7. The device asclaimed in claim 1, wherein the actuator forms part of a frame in whichat least two energy buffers are arranged, and wherein both energybuffers contain sufficient energy for both the outward and returnmovements and wherein the second energy buffer is enclosed between theframe and the assembly of rotating parts and the first energy buffer isarranged between both rotating parts and wherein only the second energybuffer generates energy to the assembly of rotating parts for theoutward movement, while at the end of the outward movement the firstenergy buffer absorbs the remaining kinetic energy as potential energyand together therewith contains sufficient energy for the returnmovement, wherein the second energy buffer is fixedly connected with theone outer end to the frame and with the other outer end engages on themass via a stop so that the charged energy buffer, when the locking isreleased, can generate its energy directly to the assembly of therotating parts over a certain angle or stroke, whereafter the assemblyof rotating parts loses contact with this energy buffer and movesfurther on the basis of the kinetic energy that is present, whereafterthe actuating element, rotating mass and the second energy buffertogether rotate further.
 8. The device as claimed in claim 7, whereinthe first and the second energy buffer are adapted to contain sufficientenergy for both the outward and return movements and wherein both energybuffers generate energy for the outward movement to the assembly ofrotating parts.
 9. The device as claimed in claim 7, wherein only thefirst energy buffer is adapted to generate energy for the outwardmovement and wherein the first and the second energy buffer are used tostore the remaining kinetic energy at the end of the outward movementand to provide energy to the return movement.
 10. The device as claimedin claim 7, wherein in addition to the first energy buffer two extraenergy buffers are used, wherein the second energy buffer is deployedfor the outward movement and the first and third energy buffer are usedfor the return movement and wherein the first energy buffer, which formspart of the assembly of rotating parts, mainly ensures the correctpressure between movable pin and stop at the end of the outward movementand wherein the remaining kinetic energy is stored in the first andthird energy buffer for the purpose of the return movement.
 11. Thedevice as claimed in claim 1, wherein an auxiliary energy buffer ismounted parallel to the rotating parts which carries the rotating partsto a predetermined point in order to give the actuator a definedposition in the case that any of the intended end positions is notreached.
 12. The device as claimed in claim 1, wherein at least oneenergy buffer comprises spring means.
 13. The device as claimed in claim1, wherein at least one energy buffer comprises pneumatic means.
 14. Thedevice as claimed in claim 1, wherein at least one energy buffercomprises hydraulic means.
 15. The device as claimed in claim 1, whereinat least one energy buffer comprises electromagnetic means.
 16. Thedevice as claimed in claim 1, wherein at least one energy buffercomprises piezo-ceramic means.
 17. The device as claimed in claim 1,wherein the actuator is provided with a device for charging at least oneof the energy buffers with energy.
 18. The device as claimed in claim 6,wherein the speed of the movable pin relative to the stop can beadjusted by adapting the manner in which the rotating movement isconverted into a non-rotating movement when a non-rotatably movable pinis used, or by adapting the actuation angle of the rotatable pinrelative to the stop.